Defrost water drain trap

ABSTRACT

A refrigerator cabinet defrost water drain trap positioned in the bottom wall of the front opening cabinet which provides a liquid trap in the form of a cup-shaped container designed to receive the lower discharge end of a drain tube. The container encloses the lower end of the drain tube such that the container&#39;&#39;s free overflow edge determining liquid level is positioned a defined distance above the discharge end of the drain tube whereby the liquid in the container provides a hydraulic suction head which normally seals the drain tube against entry of outside air into the cabinet. The differential movement of the liquid levels provides a momentary vacuum release air passage through the drain tube to permit the entrance of a limited quantity of outside air into the compartment whereby substantial equalization of pressures between the interior and exterior of the cabinet is achieved to allow the cabinet door to be reopened immediately with greater ease after closing.

United States Patent Carlin et al.

[54] DEFROST WATER DRAIN TRAP [72] Inventors: Ralph E. Carlin; Ralph R.Rigg,

both of Dayton, Ohio 10/ 1954 Caropico ..62/4l0 Corporation,

[451 Oct. 10,1972

Primary Examiner-William J. Wye Attom'ey-William S. Pettigrew, FrederickM. Ritchie and Edward P. Barthel ABSTRACT A refrigerator cabinet defrostwater drain trap positioned in the bottom wall of the front openingcabinet which provides a liquid trap in the form of a cupshapedcontainer designed to receive the lower discharge end of a drain tube.The container encloses the lower end of the drain tube such that thecontainers free overflow edge determining liquid level is positioned adefined distance above the discharge end of the drain tube whereby theliquid in the container provides a hydraulic suction head which normallyseals the drain tube against entry of outside air into the cabinet. Thedifferential movement of the liquid levels provides a momentary vacuumrelease air passage through the drain tube to permit the entrance of alimited quantity of outside air into the compartment whereby substantialequalization of pressures between the interior and exterior of thecabinet is achieved to allow the cabinet door to be reopened immediatelywith greater ease after closing.

DEFROS'I WATER DRAIN TRAP This invention relates to refrigeratingapparatus and particularly to household refrigerator defrost water draintraps permitting vacuum release which equalizes inside and outsidepressures to allow the door to be reopened immediately with greater easeafter closing, when the freezer or refrigerator is operating.

Present day household refrigerators are usually of the two-compartmenttype having above and below freezing refrigerated cabinets commonlyreferred to as overand-under or side-by-side refrigerators, wherein eachcompartment is arranged with a front access opening that is covered witha hingedly mounted door or closure member. In such two doorrefrigerators it has been found necessary to minimize inner leakagearound the access openings of the compartments and accordingly veryefficient and highly effective gasket seals have been developed. Withthe advent of magnetic gaskets or seals it has been possible not only toimprove the sealing of the refrigerator compartments but also to havesuch seals serve as the sole means for holding the doors closed. Anexample of such a magnetic gasket is disclosed in U.S. Pat. No.3,075,258 issued Jan. 29, 1963, assigned to the same assignee as theinstant application. Some prior art refrigerator cabinets have dealtwith the problem of a vacuum release for refrigerators by the provisionof a vacuum release passage located on the access door controlled by avalve arrangement to 'prevent the escape from the cabinet of cold airbut which opens to allow room air to flow through the passage to relieveany vacuum condition which may exist in the refrigerator compartment.Examples of this type of solution may be found in U.S. Pat. No.3,027,735 issued Apr. 3, 1962 to J. J. Preatle et al. and U.S. Pat. No.3,167,931 issued Feb. 2,1965 to Bryson.

It is accordingly an object of the present invention to provide acondensate collecting means for a front opening refrigerator 'cabinetthat is effective at all times for sealing the drain tube against theentrance of foreign matter while functioning to reduce the difference inpressure between the interior and exterior of the cabinet to facilitatethe opening of the refrigerator door closing the cabinet opening.

It is still another object of the invention to provide an improveddefrost water drain trap for a refrigerator cabinet that includescooperative engaging means between a drain tube and liquid trapcontainer whereby the container and drain tube are positioned toestablish a hydraulic suction head which normally seals the drain tubeagainst entry of outside air into the cabinet while providing amomentary vacuum release air passage through the drain tube operative topermit the entrance of a sufficient quantity of outside air into thecompartment such that substantial equalization of air pressures occursto allow the refrigerator cabinet door to be reopened after closing withgreater ease.

In the drawings:

FIG. 1 is a perspective view of a refrigerator cabinet of the topfreezer type incorporating the present invention;

FIG. 2 is a vertical section of the bottom wall portion of therefrigerator cabinet taken along the lines 22 of FIG. 1;

FIG. 3 is an enlarged vertical section with portions broken away of thedrain trap assembly of FIG. 2;

FIG. 4 is a horizontal section taken on the line 44 of FIG. 3;

FIG. 5 is a top plan view of a portion of the bottom wall of therefrigerator taken on the line 5-5 of FIG. 3. Referring now to thedrawings, in FIG. 1 there is illustrated an insulated refrigeratorcabinet 12 having an upright outer shell 14 formed in part by a rearwall portion 15 (FIG. 2) joining spaced apart side walls, only side wall16 being shown, a top wall 17 and an irregular bottom wall 20. Theinsulated cabinet includes, as seen in FIG. 2, a support base 22 in partdefined by depending skirt 23 thereon which encloses a machinerycompartment 24 having a rear access opening 26 formed in the back of thesupport base 22 closed by a plate 28. Within the outer shell 14 of thecabinet 12 is located an inner liner indicated at 30 having a rear wall32, spaced apart side walls, only one of which is shown at 34, a bottomwall 38, and a top 39. Suitable insulation (not shown) fills the spacebetween liner 30 and the outer shell 14 of the cabinet.

Within the liner 30 is located a horizontally disposed thermallyinsulated partition assembly 46 which divides the liner 30 into an upperor top freezer compartment 48 at the top of the cabinet and a bottomabove-freezing space or compartment 49 for general food storage. The topfreezer compartment 48 is closed by a top door closure 56 that isrepresentatively illustrated as being hinged on the cabinet 12 andmovable from the open position shown in FIG. 1 to a closed positionwhere a continuously formed magnetic door gasket or seal58 on the insideface of the door 56 engages the cabinet 12 around a front cabinetopening 59 to the freezer compartment.

The refrigerator further includes a bottom door 60 having a magneticsealing gasket 62 on the inside surface thereof formed continuouslyaround the outer perimeter thereof that is engageable with the cabinet12 to close lower front cabinet opening 63 into the compartment 49.Certain features of this type refrigerator are shown in U.S. Pat. No.3,455,119, issued July 15, 1969, assigned to the assignee of the instantapplication the disclosure of which is incorporated by reference herein.

The refrigerator cabinet 12 includes an air flow cooling system of thetype more specifically set forth in U.S. Pat. No. 3,261,173 issued July19, 1966, to l. L. Gould, assigned to the same assignee as the instantapplication, the disclosure of which is incorporated by referenceherein. For purposes of the present invention it is only necessary toindicate that the cooling system includes a motor driven fan (not shown)for directing air through the freezer compartment 48, thence throughgrille openings (not shown) for distribution throughout the abovefreezing food storage compartment 49.

As seen in FIG. 2 the bottom wall 20 includes a horizontal sheet metallower front portion 51 and higher rear portion 52 of the outer shell 14.Spaced from and substantially parallel to the portions 51 and 52 of wall20 is the irregular bottom 38 of plastic liner 30 of the refrigeratorand supported from the adjacent outer shell wall 20 by thermal foaminsulation 65. The liner bottom 38 has a lower front insulated wall 66and a stepped-up rear wall 67 which is raised substantially above thefront wall 66 to provide adequate space beneath for the sealed motorcompressor unit 68.

The lower liner wall 66 is inclined toward the front of the refrigeratorand is formed with a depressed trough or recess 69 extendingtransversely across the lower liner wall 66 to each of the inner sidewalls of the liner 30. The trough 69 is sloped inwardly from both sidewalls toward a circular opening 70 therein positioned adjacent side wall34 for location of drain assembly 64. The trough 69 received drain tubemember 71, which is tightly secured in the opening 70 by an uppersealing grommet 72 formed integral with and surrounding the upper end ofthe drain tube 71 such that it envelops the rim of the opening 70. Aflanged insert sleeve 73 preferably formed of high density plasticmaterial is inserted into the upper sealing grommet 72 to provide anairtight fit to prevent air flow between the machinery compartment 24and the above-freezing compartment 49. The portion 51 of bottom wall hasa circular opening 74 such that a lower sealing grommet 76 formedintegral with intermediate portion of the drain tube 71 envelops the rimof opening 74. The lower end of the drain tube 71 includes a drain pipe78 that is adapted to extend below the wall portion 51 a defineddistance which in the instant form is about 0.43 in. for a purpose to beexplained. As a specific example the drain tube member 71 is formed froma suitable rubber material such as ethylene propylene terpolymer havinga material thickness of about 0.040 in. and a shore hardness of about50. The drain pipe 78 has an outside diameter of about 0.60 in. and aninside diameter of about 0.52 in. The portion of the drain tube member71 between the grommets 72 and 76 is formed as a bulbous conduit 79 toallow for the drain tube member 71 to adjust to variations in spacingbetween the walls 51 and 66.

The water container portion of the drain assembly 64, indicatedgenerally at 80, is preferably formed of high density polyethyleneplastic having a lower hemispheric bowl portion 82 and an upstandingstem portion 84 formed integral with the bowl portion 82 and positionedon the principal vertical axis thereof. The stem portion 84 is spiderlike in cross section preferably providing four upwardly tapered ribs 86in a cross or X- shaped grid pattern to block the entrance of solid foodparticles or the like. Each of the ribs 86 has its upper free end offsetto form a reduced section 87 that is adapted to extend through theinsert sleeve central opening 85 while the upper edges 88 of the ribsterminate in a smooth curve manner for ease of assembly with the draintube member 71. The upwardly tapered ribs 86 are adapted for wedge-likeengagement with the opening of the lower grommet 76 to insure aninterference or friction fit to fixedly retain the container assembly 80as shown in FIG. 3 and provide a substantially airtight seal betweenperipheral groove 77 of the lower grommet 76 and the rim of the lowercircular opening 74. The insert sleeve 73 is dimensioned to establish afriction or force fit in the central opening of upper grommet 72 toprovide a substantially airtight sealed closure between the peripheralgroove 75 of the upper grommet 72 and the opening 70.

The bowl portion 82 has its hemispheric shape terminating in a circularhorizontal flange 90 defining a cylindrical barrel 92 having uniformlyspaced upwardly projecting spacers or cogs 94 defining a plurality ofannular spaced overflow openings 96 as shown in FIG. 4.

The spaced openings 96 have their horizontal arcuate overflow rims 99located a defined vertical distance above the bottom edge 97 of drainpipe 78, by virtue of the upper faces 98 of spacers 94 contacting thewall 51, to thereby establish a defined suction head indicated by thedimension H of FIG. 3.

As a specific example the water container has an inside diameter ofabout 1.00 in. and a maximum depth of about 0.85 in. from the bowlcenter to the overflow rims 99, while the spacers 94 have a height ofabout 0.22 in. The dimension H or suction head for the disclosed form isabout 0.30 in.

As the evaporator is defrosted the moisture of a condensate drainingtherefrom will flow down the liner 30 sidewalls to the liner bottom 38and thence via front and rear walls 66, 67 to be collected in trough 69which is sloped from each liner side wall toward the insert sleeveopening permitting the drain water to rise in the container 80 until itreaches the overflow rims 99 whence it will overflow and fall into drainpan 100 where it will be evaporated by the exposure to the atmosphereassisted by the heat generated in the machine compartment 24. It will benoted that super heat coil 102 in the machinery compartment is a tubeand fin coil located adjacent the center of the compartment and islaterally spaced from the drain assembly 64 to insure that the coil 102will not be splashed by the overflow. As seen in FIG. 1 the drain pan100 extends substantially throughout the floor of the machinerycompartment to provide a maximum liquid exposure such that additionalheating means is not required for evaporation of the drain water.

In operation when the door 60 is opened some of the cold air in thecompartment 49 will fall out into the room, and when the door isreclosed and the warmer air from the room which is moved into thecompartment immediately starts cooling and upon cooling contracts, thusreducing the pressure therewithin and forming a negative pressure.Because the above freezing space 49 is in communication with thecompartment 48 the pressure differential between the compartments 48 and49 and the room may become sufficient to prevent the reopening of thedoors or else require an abnormal amount of force to allow the doors tobe reopened. It was found by tests that if a suction head H ismaintained in the drain assembly 64 as described this differentialpressure is sufficient to force a portion of the drain water in thecontainer 80 upwardly into the drain tube 71 thereby creating amomentary air passage through the drain tube into the compartment 49 tosubstantially equalize the pressure differential inside and outside thecabinet 14 to again permit easy opening of the doors. The drain water isautomatically returned to the container 80 by gravity flow from thedrain tube 71 to again return the condensate to its first maximumpredetermined level in the container 80 and drain pipe 78, determined bythe overflow rims or free edges 99, the distance H above the secondpredetermined level determined by the discharge or bottom drain pipe end97 to again seal the drain tube 71.

The liner 30, defining upper and lower refrigerated compartments 48, 49,has a total volume in the instant embodiment in the general range ofabout 15 to 17 cubic feet with the lower compartment 49 varying involume in the general range of about 10 to 12 cubic feet and the uppercompartment having a volume of approximately 5 cubic feet.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is:

l. The combination of a refrigerating cabinet including outer wallssurrounding and spaced from an inner liner means, said liner meansforming a box-like sealed food storage compartment within said cabinetand having an access opening, a refrigerating system for cooling saidcompartment and at times causing moisture to condense out of the airtherein in the form of condensate, a door hingedly mounted with respectto said cabinet and adapted to close the access opening for said foodstorage compartment, magnetic door gaskets circumscribing the jointureof said door with said inner liner means for sealing said access openingin an airtight manner, said liner means having a drain opening in thebottom thereof for draining said condensate from said food storagecompartment, a gravity drain tube having an inlet end connected to saiddrain opening and a discharge end-below said inlet end and outside saidfood storage compartment, means for sealing the connection of said inletend of said drain tube with said drain opening in an airtight manner, anopen-top container below said discharge end of said drain tube forcollecting said condensate and for enclosing said discharge end tosubmerge said discharge end in said condensate and forming a trap toprevent the entrance of contaminants from the atmosphere into said foodstorage compartment, whereby successive openings of said door withrespect to said food storage compartment in a relatively short timeinterval is resisted by a negative pressure in said compartment effectedby said refrigerating system and the airtight manner of openings leadingto said compartment, means for retaining said container in fixedrelation with said drain tube, said container in forming said trap beingadapted when said door is closed to maintain said condensate at a firstmaximum predetermined level in said container and said drain tube withrespect to the discharge end of said drain tube, said first maximumpredetermined level in said container tending to lower toward thedischarge end of said drain tube to a second predetermined level whilesaid first predetermined level in said drain tube tends to raise as theresult of said door being opened against the resistance of said negativepressure to the opening of said door, said discharge end located apredetermined height below said first maximum predetermined level ofcondensate in said container, said predetermined height being sufficientto establish a suction head substantially equal to the differencebetween said first and second predetermined levels whereby a limitedquantity of outside air is admitted into said drain tube through saiddischarge end and thence into said food storage compartment to reducesaid negative pressure and thereby the resistance to opening said door.

2. The combination of a refrigerating cabinet including outer side, top,bottom and back walls surrounding and spaced from an inner liner means,said liner means forming a box-like sealed food storage compartmentwithin said cabinet and having an access opening, a refrigerating systemfor cooling said compartment and at times causing moisture to condenseout of the air therein in the form of condensate, a door hingedlymounted withrespect to said cabinet and adapted to close the accessopening for said food storage compartment, magnetic door gasketscircumscribing the jointure of said door with said inner liner means forsealing said access opening in an airtight manner, said -liner meanshaving a bottom wall spaced from .said cabinet bottom wall, said linerbottom wall and said cabinet bottom wall having aligned drain openingstherein for draining the condensate from said food storage com partment,a gravity drain tube having an inlet end connected to said liner drainopening and a discharge end extending through said cabinet bottom walldrain opening and outside said food storage compartment, said drain tubeformed of rubber-like material having upper and lower integral resilientsealing grommets fastened in said liner and cabinet bottom wall openingsrespectively, means for sealing said drain tube grommets with saidaligned openings in an airtight manner, an opentop container below saiddischarge end of said drain tube for collecting the condensate and forenclosing said discharge end to submerge said discharge end in thecondensate and forming a trap to prevent the entrance of contaminantsfrom the atmosphere into said food storage compartment, wherebysuccessive openings of said door with respect to said food storagecompartment in a relatively short time interval is resisted by anegative pressure in said compartment effected by said refrigeratingsystem and the airtight manner of openings leading to said compartment,means for retaining said container in fixed relation with said draintube, said container in forming said trap being adapted when said dooris closed to maintain said condensate at a first maximum predeterminedlevel in said container and said drain tube with respect to thedischarge end of said drain tube, said container having its uppercondensate overflow rim provided with a plurality of spaced verticallyextending cogs contacting the outer face of said cabinet bottom wallwhereby a predetermined height is established between said drain tubedischarge end and said container overflow rim, said first maximumpredetermined level in said container established by said overflow rimtending to lower to a second predetermined level established by saiddischarge end while said first predetermined level in said drain tubetends to raise as the result of said door being opened against theresistance of said negative pressure to the opening of said door, saidpredetermined height being sufficient to establish a suction headsubstantially equal to the difference between said first and secondpredetermined levels whereby a limited quantity of outside air isadmitted into said drain tube through said discharge end and thence intosaid food storage compartment to reduce said negative pressure andthereby the resistance to opening said door.

3. The combination of a refrigerating cabinet including outer side, top,bottom and back walls surrounding and spaced from an inner liner means,said liner means forming a lower box-like sealed food storagecompartment within the range of 10 to 12 cubic foot capacity within saidcabinet and having an access opening, said liner forming an upperbox-like sealed freezer compartment of approximately five cubic feetcapacity and having an access opening, a refrigerating system forcooling said upper and lower compartments and at times causing moistureto condense out of the air therein in the form of condensate, a pair ofdoors hingedly mounted with respect to said cabinet and adapted to closeeach of the access openings for said food storage compartment, magneticdoor gaskets circumscribing the jointure of said doors with said innerliner means for sealing said access openings in an airtight manner, saidliner means having a bottom wall spaced from said cabinet bottom wall,said liner bottom wall and said cabinet bottom wall having aligned drainopenings therein for draining the condensate from said food storagecompartment, a gravity drain tube having an inlet end connected to saidliner drain opening and a discharge end extending through said inlet endand outside said food storage compartment, said drain tube formed ofrubber-like material having upper and lower integral resilient sealinggrommets fastened in said liner and cabinet bottom wall openingsrespectively, each said grommet having a central opening and aperipheral groove for receiving the peripheral edge of its associatedopening, said upper grommet opening having a sleeve inserted thereindimensioned to establish a substantially airtight seal with said lineropening, an open-top container below said discharge end of said draintube for collecting said condensate and for enclosing said discharge endto submerge said discharge end in said condensate and forming a trap toprevent the entrance of contaminants from the atmosphere into said foodstorage compartment, whereby successive opening of said doors withrespect to their respective compartments in a relatively short timeinterval is resisted by a negative pressure in said compartmentseffected by said refrigerating system and the airtight manner ofopenings leading to said compartments, said container comprising anintegrally formed semi-cylindrical bowl having an upwardly taperedvertical stem extending from the inner face of said bowl such that theaxis of said stem coincides with the principal axis of said bowl, saidstem having a spider-like cross section forming radial rib members, saidstem extending through said lower grommet opening and said insert sleevewhereby said upwardly tapered ribs provide wedge-like engagement withsaid lower grommet opening to provide an interference fit therebetweenwhereby said container is retained in fixed relation with said draintube while forming a substantially airtight seal between said lowergrommet and its associated bottom wall opening, said container havingits upper condensate overflow rim provided with a plurality of spacedvertically extending cogs contacting the outer face of said cabinetbottom wall whereby a predetermined height is established between saiddrain tube discharge end and said container overflow free edge, saidcontainer in forming said trap being adapted when said door is closed tomaintain said condensate at a first maximum predetermined level in saidcontainer and said drain tube with respect to the discharge end of saiddrain tube, said first maximum predetermined level in said containerestablished by said overflow rim tending to lower to a secondpredetermined level established by said drain tube discharge end whilesaid first predetermined level in said drain tube tends to raise as theresult of sai door bein o eneda ain st the resistance of said negati vepressur t?) the o penmg of said door, said discharge end located apredetermined height of the order of 0.30 in. below said overflow rim ofsaid container, said predetermined height being sufficient to establisha suction head substantially equal to the difference between said firstand second predetermined condensate levels whereby a limited quantity ofoutside air is admitted into said drain tube through said discharge endand thence into said lower food storage compartment and thence to saidupper freezer compartment to reduce said negative pressure and therebythe resistance to opening said doors.

4. The combination as defined in claim 3 wherein said radial rib membersextend above said upper grommet opening to guard against foreign matterblocking said upper grommet opening.

1. The combination of a refrigerating cabinet including outer walls surrounding and spaced from an inner liner means, said liner means forming a box-like sealed food storage compartment within said cabinet and having an access opening, a refrigerating system for cooling said compartment and at times causing moisture to condense out of the air therein in the form of condensate, a door hingedly mounted with respect to said cabinet and adapted to close the access opening for said food storage compartment, magnetic door gaskets circumscribing the jointure of said door with said inner liner means for sealing said access opening in an airtight manner, said liner means having a drain opening in the bottom thereof for draining said condensate from said food storage compartment, a gravity drain tube having an inlet end connected to said drain opening and a discharge end below said inlet end and outside said food storage compartment, means for sealing the connection of said inlet end of said drain tube with said drain opening in an airtight manner, an open-top container below said discharge end of said drain tube for collecting said condensate and for enclosing said discharge end to submerge said discharge end in said condensate and forming a trap to prevent the entrance of contaminants from the atmosphere into said food storage compartment, whereby successive openings of said door with respect to said food storage compartment in a relatively short time interval is resisted by a negative pressure in said compartment effected by said refrigerating system and the airtight manner of openings leading to said compartment, means for retaining said container in fixed relation with said drain tube, said container in forming said trap being adapted when said door is closed to maintain said condensate at a first maximum predetermined level in said container and said drain tube with respect to the discharge end of said drain tube, said first maximum predetermined level in said container tending to lower toward the discharge end of said drain tube to a second predetermined level while said first predetermined level in said drain tube tends to raise as the result of said door being opened against the resistance of said negative pressure to the opening of said door, said discharge end located a predetermined height below said first maximum predetermined level of condensate in said container, said predetermined height being sufficient to establish a suction head substantially equal to the difference between said first and second predetermined levels whereby a limited quantity of outside air is admitted into said drain tube through said discharge end and thence into said food storage compartment to reduce said negative pressure and thereby the resistance to opening said door.
 2. The combination of a refrigerating cabinet including outer side, top, bottom and back walls surrounding and spaced from an inner liner means, said liner means forming a box-like sealed food storage compartment within said cabinet and having an access opening, a refrigerating system for cooling said compartment and at times causing moisture to condense out of the air therein in the form of condensate, a door hingedly mounted with respect to said cabinet and adapted to close the access opening for said food storage compartment, magnetic door gaskets circumscribing the jointure of said door with said inner liner means for sealing said access opening in an airtight manner, said liner means having a bottom wall spaced from said cabinet bottom wall, said liner bottom wall and said cabinet bottom wall having aligned drain openings therein for draining the condensate from said food storage compartment, a gravity drain tube having an inlet end connected to said liner drain opening and a discharge end extending through said cabinet bottom wall drain opening and outside said food storage compartment, said drain tube formed of rubber-like material having upper and lower integral resilient sealing grommets fastened in said liner and cabinet bottom wall openings respectively, means for sealing said drain tube grommets with said aligned openings in an airtight manner, an open-top container below said discharge end of said drain tube for collecting the condensate and for enclosing said discharge end to submerge said discharge end in the condensate and forming a trap to prevent the entrance of contaminants from the atmosphere into said food storage compartment, whereby successive opeNings of said door with respect to said food storage compartment in a relatively short time interval is resisted by a negative pressure in said compartment effected by said refrigerating system and the airtight manner of openings leading to said compartment, means for retaining said container in fixed relation with said drain tube, said container in forming said trap being adapted when said door is closed to maintain said condensate at a first maximum predetermined level in said container and said drain tube with respect to the discharge end of said drain tube, said container having its upper condensate overflow rim provided with a plurality of spaced vertically extending cogs contacting the outer face of said cabinet bottom wall whereby a predetermined height is established between said drain tube discharge end and said container overflow rim, said first maximum predetermined level in said container established by said overflow rim tending to lower to a second predetermined level established by said discharge end while said first predetermined level in said drain tube tends to raise as the result of said door being opened against the resistance of said negative pressure to the opening of said door, said predetermined height being sufficient to establish a suction head substantially equal to the difference between said first and second predetermined levels whereby a limited quantity of outside air is admitted into said drain tube through said discharge end and thence into said food storage compartment to reduce said negative pressure and thereby the resistance to opening said door.
 3. The combination of a refrigerating cabinet including outer side, top, bottom and back walls surrounding and spaced from an inner liner means, said liner means forming a lower box-like sealed food storage compartment within the range of 10 to 12 cubic foot capacity within said cabinet and having an access opening, said liner forming an upper box-like sealed freezer compartment of approximately five cubic feet capacity and having an access opening, a refrigerating system for cooling said upper and lower compartments and at times causing moisture to condense out of the air therein in the form of condensate, a pair of doors hingedly mounted with respect to said cabinet and adapted to close each of the access openings for said food storage compartment, magnetic door gaskets circumscribing the jointure of said doors with said inner liner means for sealing said access openings in an airtight manner, said liner means having a bottom wall spaced from said cabinet bottom wall, said liner bottom wall and said cabinet bottom wall having aligned drain openings therein for draining the condensate from said food storage compartment, a gravity drain tube having an inlet end connected to said liner drain opening and a discharge end extending through said inlet end and outside said food storage compartment, said drain tube formed of rubber-like material having upper and lower integral resilient sealing grommets fastened in said liner and cabinet bottom wall openings respectively, each said grommet having a central opening and a peripheral groove for receiving the peripheral edge of its associated opening, said upper grommet opening having a sleeve inserted therein dimensioned to establish a substantially airtight seal with said liner opening, an open-top container below said discharge end of said drain tube for collecting said condensate and for enclosing said discharge end to submerge said discharge end in said condensate and forming a trap to prevent the entrance of contaminants from the atmosphere into said food storage compartment, whereby successive opening of said doors with respect to their respective compartments in a relatively short time interval is resisted by a negative pressure in said compartments effected by said refrigerating system and the airtight manner of openings leading to said compartments, said container comprising an integrally formed semi-cylindrical bowl having an Upwardly tapered vertical stem extending from the inner face of said bowl such that the axis of said stem coincides with the principal axis of said bowl, said stem having a spider-like cross section forming radial rib members, said stem extending through said lower grommet opening and said insert sleeve whereby said upwardly tapered ribs provide wedge-like engagement with said lower grommet opening to provide an interference fit therebetween whereby said container is retained in fixed relation with said drain tube while forming a substantially airtight seal between said lower grommet and its associated bottom wall opening, said container having its upper condensate overflow rim provided with a plurality of spaced vertically extending cogs contacting the outer face of said cabinet bottom wall whereby a predetermined height is established between said drain tube discharge end and said container overflow free edge, said container in forming said trap being adapted when said door is closed to maintain said condensate at a first maximum predetermined level in said container and said drain tube with respect to the discharge end of said drain tube, said first maximum predetermined level in said container established by said overflow rim tending to lower to a second predetermined level established by said drain tube discharge end while said first predetermined level in said drain tube tends to raise as the result of said door being opened against the resistance of said negative pressure to the opening of said door, said discharge end located a predetermined height of the order of 0.30 in. below said overflow rim of said container, said predetermined height being sufficient to establish a suction head substantially equal to the difference between said first and second predetermined condensate levels whereby a limited quantity of outside air is admitted into said drain tube through said discharge end and thence into said lower food storage compartment and thence to said upper freezer compartment to reduce said negative pressure and thereby the resistance to opening said doors.
 4. The combination as defined in claim 3 wherein said radial rib members extend above said upper grommet opening to guard against foreign matter blocking said upper grommet opening. 